| 摘要 |
An apparatus comprises a charged particle beam source and a target (1) for a charged particle beam. The target comprises a concave outer surface which is at least a segment of a cylinder (2) having a periodically structured surface (4). The charged particle beam is directed parallel to the axis of the cylinder (2), with the distance of the charged particle beam from the surface being less than or equal to twice the period of the periodically structured surface (4) in a direction perpendicular to the charged particle beam. The width of the charged particle beam in a direction perpendicular to the charged particle beam and parallel to the outer surface of the target is less than twice the period of the periodically structured surface (4) in a direction perpendicular to the charged particle beam. |
